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mine to Pond D. Since 1984, flows from these ponds have changed Foidel Creek from <br />an ephemeral to a perennial stream. Peak dischazges from the ponds do not seem to <br />have changed significantly because the spoil spring water would have dischazged as <br />snowmelt runoff anyway. <br />Water Quality <br />Summaries of the water quality data for the eight Mine 1 ponds aze presented on Tables <br />57 through 71 and on Figures 44 and 49 through 53. The field conductivity solids data <br />shows some typical seasonal variation: the water quality improves during spring <br />runoff. Ponds A, B, D, E, F, and H appear to be impacted by spoil spring inflows. <br />The discharge rates from Ponds B, E and H aze not significant during irrigation season <br />and therefore these ponds do not cause any significant impacts. The mean 1991 <br />irrigation season field conductivity for the ponds A, D and F aze approximately 2700, <br />3100 and 3700 respectively. These values are similaz to those measured in the previous <br />three years. These values are also reflected in the conductivity level in Foidel Creek at <br />• Station 8 which has a mean irrigation season level of about 2800 umhos/cm. <br />For most of the ponds, no sufficient increased levels in any parameters were observed <br />in 1991. For the ponds effected by spoil springs increased calcium, magnesium, <br />sulfate, dissolved solids and SAR were observed. <br />The 1991 irrigation season mean field conductivity level in Trout Creek below Middle <br />Creek ranged between only 10 and 35 umhos/cm higher than that above Middle Creek. <br />The relatively insignificant downstream increase in conductivity reflects the very low <br />flows recorded for the Foidel and Middle Creeks during the 1991 irrigation season. <br />The observed Trout Creek conductivity increase was not enough to cause material <br />damage and occurred during a period of very high irrigation withdrawals. Also, the <br />water quality of Trout Creek was better than maximum levels predicted in the salt- <br />loading calculations performed as part of the "probable hydrologic impacts" section of <br />the mine permit application. <br />Only insignificant dischazges during spring runoff were recorded from Mine No. 2 <br />• Ponds in 1991. Therefore no impacts to Fish Creek were observed. <br />- 14 - <br />